ABB Relion 670 Series Application Manual page 44

Section 4
Analog and binary signal transfer for line differential protection
Table 3:
Station
Type of fault
Object
Setting
Characteristic
High set stage
It is important to achieve a proper back-up protection. The short circuit protection on the
outgoing bays and on the LV side of the transformer are set according to a prepared
selectivity chart. An example in Figure
on the LV side is 14 MVA, and Normal Inverse has k=0.12 to give back-up to outgoing bays'
relays which are extremely inverse and selective to remote fuses.
IEC14000047 V1 EN-US
Figure 38: Selectivity chart
38
Backup protection example data
Tap transformer 10 MVA
Three phase fault
1 = 10 kV Line A
2 MVA
IEC Extr.inverse, k=0.5,
A=80, p=2
14 MVA
© Copyright 2017 ABB. All rights reserved
2 = T1 10 kV 50/51
14 MVA
IEC Norm.inverse k=0.12,
A=0.14, p=0.02
- - - -
38 shows that the setting of the short circuit protection
Communication set-up, 670/650 series
1MRK 505 382-UEN E
3 = 130 kV 87L
(ImaxAddDelay)
20 MVA
IEC Norm.inverse k=0.18,
A=0.14, p=0.02
- - - -
IEC14000047 -1-en.ai
Application Guide